im interested with Q5III, main usage are for browse webpage, youtube, access google playstore/apps..
- are there any known issue with google playstore? any apps not playable, slow?
- is web browsing and youtube playback fast?

Thank you for inquiry. Since your requirement are browse webpage, youtube, access google playstore/apps, then Q5III is a bit over design. The entry level H8 could be sufficient for browsing, YuoTube and Google Play Store.
https://forum.lowyat.net/index.php?showtopic=3228258&hl=
Please find below my answer :
- Android is open Operating System Support different CPU architectures such as for ARM, x86, MIPS and etc. It depend on the skill of the app developer. A good developer will design the apps to support multiple architectures with multiple SOC. A bad developer design an app supported limited hardware. For example, the first version of AstroOTG support only Samsung Pad, Samsung Note only. Therefore I could not guaranteed you Himedia box could support 100% apps in the Google Play Store. Further detail, pls refer to the link http://developer.android.com/google/play/p...tiple-apks.html

- Web browsing response time is depend on your internet speed. YouTube app is download from original Google Play store.